Electrochemical Reductive Alkylation of Azomethines with 1‐Bromadamantane and 9‐Bromo‐tetrahydro‐exo‐dicyclopentadiene
Electrochemically generated radical anions of Schiffbases 1a—11 react in DMF and in the presence of bridgeheadhalogenides as 1‐bromoadamantane and 9‐bromo‐tetrahydro‐exo‐dicyclopentadiene to 1‐[α‐(aryl‐ or alkylamino)‐α‐arylmethyl]‐adamantanes and the correspondent 9‐tetrahydro‐exo‐dicyclopentadienes. In the course of SET‐mechanism originating bridgehead radicals couple with the azomethine‐radicalanions at the position of the highest unpaired electron density, which is predominantly the carbon of the C,N‐double bond. Only in cases when this density at the N‐atom is relatively high, or steric hindrance impedes C‐alkylation, N‐hydroalkylated products as N,N‐disubstituted 1‐aminoadamantanes and 9‐amino‐tetrahydro‐exo‐dicyclopentadienes are formed. Product distribution, cyclic‐voltammetric results and quantumchemical data are discussed in terms of mechanism.